Introduction
Cells need oxygen to live . While on the one hand this molecule is essential for the survival of the cells themselves, on the other, in particular circumstances, it can become harmful and give rise to free radicals.
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Free radicals
Free radicals are molecules or ions that contain one or more unpaired electrons and are capable of autonomous existence.
Free radicals are produced in most of the body’s cells (mitochondria) as a by-product of certain metabolic reactions.
Free radicals are considered responsible for most degenerative diseases, aging and , perhaps, even cancer ( mutations ).
Many factors can trigger the generation of free radicals:
- ENVIRONMENTAL FACTORS: pollution, active and passive smoking , ultraviolet rays , prolonged psychophysical stress , alcohol
- FACTORS RELATED TO THE SUBJECT: electron transport in the mitochondria , fatty acid metabolism , cytochrome p450 reactions , phagocytic cell reconditioning systems
Among the most important free radicals found in aerobic cells, such as human cells, are superoxides (O 2 – ), hydrogen peroxide also known as hydrogen peroxide (H 2 O 2 ) and singlet oxygen.
All cellular structures can be damaged by interaction with oxidizing species:
- PHOSPHOLIPIDS : alteration of membrane fluidity
- NUCLEIC ACIDS : appearance of breaking points in the double helix of DNA with increased risk of mutations
- PROTEINS : metabolic ( enzyme ) and structural alterations
Endogenous antioxidants
The body has developed numerous mechanisms to protect itself from the harmful effects of free radicals; there are, for example, some enzymes capable of decomposing and sequestering oxidizing agents.
Among these endogenous antioxidants we remember superoxide dismutase, catalase and the most effective antioxidant, glutathione ( whose integration takes place through one of the precursor amino acids , N-acetyl cysteine ).
Glutathione incorporates selenium, an exogenous antioxidant that appears to decrease the risk of cancer.
The cell also has additional defense mechanisms at its disposal in case the function of the endogenous antioxidants is not sufficient.
In recent years there has been a lot of talk about the antioxidant power of melatonin which according to some studies exceeds the “scavenger” activity of glutathione by five times.
Exogenous antioxidants
Some substances present in foods and in some food supplements are able to intervene favorably in detoxification processes, activating biological repair systems. These natural antioxidants are vitamins A , C, E, selenium , carotenoids , lycopene , coenzyme Q-10 and lipoic acid . For further information see: Antioxidant foods
Antioxidants and Sport
During aerobic physical exercise, the body’s oxygen consumption can increase up to 20 times and in skeletal muscle up to 100 times. While on the one hand this mechanism allows for an increase in the amount of energy produced, on the other hand it also dangerously increases the production of oxidizing agents.
In general, muscle oxidative stress is increased by acute exercise and decreased by training.
Sports activity also improves the elimination mechanisms by enhancing the activity of endogenous antioxidants. This characteristic explains why physical exercise makes people who practice it appear more beautiful and young on a regular basis.
